Explanation

The carbon compound which forms the endoskeleton and exoskeleton of animals is calcium carbonate.

Seashells are the exoskeletons of mollusks such as snails, clams oysters and many others.

Such shells have three distinct layers.

They are composed mostly of calcium carbonate with only a small quantity of protein--no more than 2 percent.

Explanation

• Humidity in the air was measured by a Hygrometer.
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• A hygrometer is an instrument used to measure relative humidity.
• Humidity is the measure of the amount of moisture in the air.
• A psychrometer is an example of a hygrometer.
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• The humidity in the air tells us about the ratio of Water vapors in the air

Explanation

• Venus, often called the "Evening Star" or "Morning Star," appears in the western sky after sunset.
• Venus is the brightest planet.
• It has an atmosphere but no moons.
• It's identical in size, chemistry and gravity.
• It has volcanoes, mountains and sand.
• It's also called Sister Planet of the Earth.

Explanation

Celestial bodies that do not have their own heat and light are known as planets. Planets are lit by the light of stars, such as our sun.

Stars: Celestial bodies that emit their own light.

Asteroids: Tiny bodies that move around the sun, found between the orbits of Mars and Jupiter.

Comets: Bodies in space that are seen by reflected light.

Explanation

Biodegradable:

Materials that decompose naturally by microorganisms.
Examples: Paper, food waste, leaves.

Non-Biodegradable:

Materials that do not decompose easily or naturally.
Examples: Plastics, metals, synthetic fibers.

Explanation

Explanation

Explanation

Evaporation happens when a liquid turns into a gas.

It can be easily visualized when rain puddles “disappear” on a hot day or when wet clothes dry in the sun.

In these examples, the liquid water is not actually vanishing—it is evaporating into a gas, called water vapor.

Explanation

Calcium oxalate is the most common compound found in kidney stones.

It forms when excess calcium and oxalate in the urine combine, creating hard crystals that can grow into stones.

Explanation